Abstract:
A point diffraction interferometer for measuring properties of a spatial impulse response function, the interferometer including: a source for generating a source beam; an optical system; an optical element including a test object located in an object plane of the optical system, the test object including a diffraction point for generating from the source beam a measurement beam that passes through the optical system, wherein the optical element also generates from the source beam a reference beam that is combined with the measurement beam to generate an interference pattern in an image plane of the optical system, the interference pattern representing the spatial impulse response function of the optical system.
Abstract:
Apparatus and methods for in situ and ex situ measurements of spatial profiles of the modulus of the complex amplitude and intensity of flare generated by an optical system. The in situ and ex situ measurements comprise interferometric and non-interferometric measurements that use an array of diffraction sites simultaneously located in an object plane of the optical system to increase signals related to measured properties of flare in a conjugate image plane. The diffraction sites generate diffracted beams with randomized relative phases. In general, the interferometric profile measurements employ phase-shifting point-diffraction interferometry to generate a topographical interference signal and the non-interferometric measurements are based on flare related signals other than topographic interference signals. The topographical interference signal and flare related signals are generated by a detector either as an electrical interference signal or electrical flare related signals or as corresponding exposure induced changes in a recording medium.